1. Field of the Invention
The present general inventive concept relates to an image reading device and an image forming apparatus having the same, and more particularly to an image reading device and an image forming apparatus having the same that is capable of duplex (double-sided) scanning.
2. Description of the Related Art
An image forming apparatus is an apparatus that prints an image on a printing medium, e.g., paper, according to an inputted image signal. An image forming apparatus may be classified as a printer, a copying machine, a multi-function printer with multiple functions of printing, copying, scanning, and the like. For example, a multi-function printer can perform a printing function of printing an image in response to image information from an external apparatus such as a computer, etc., a reading function of reading image information recorded on a document and retaining the image information in a recording medium, a copying function of printing an image in response to scanned image information, and a fax function of transmitting scanned image information to a remote place through communication links.
In order to achieve the above functions, a multi-function image forming apparatus is equipped with an image reading device to read image information recorded on a document. An example of a conventional image reading device is disclosed in Japanese Patent Laid-Open Publication No. 2005-191795. The disclosed conventional image reading device may perform duplex (double-sided) scanning. The conventional image reading device includes a first image sensor unit and a second image sensor unit, which are oppositely arranged on both surfaces of a document, to simultaneously read information recorded on both the surfaces of the document.
In this type of image reading device, because two image sensor units oppose each other and respectively irradiate light to a front surface and a rear surface of the document, the light irradiated from one image sensor unit affects the other opposite image sensor unit and deteriorates a scan quality. To address this problem, the disclosed conventional image reading device is equipped with a light shielding member that is mounted inside the image sensor unit to shield light irradiated from a light source from being transmitted to a light receiving element of the other opposite image sensor unit.
However, in the conventional image reading device, the light irradiated from the light source of the image sensor unit (e.g., the first image sensor unit) may be reflected from the light shielding member and transmitted to the light receiving element of the same image sensor unit (the first image sensor unit), which may cause the light receiving element to detect light unrelated to image information of the document and/or deteriorate a scan quality.
Also, because the light shielding member, which is formed in a plastic plate or coated with paint, is mounted inside the image sensor unit, an inner structure of the image sensor unit and an assembling process of the image sensor unit may become complicated.
Also, when two image sensor units oppositely arranged on both the surfaces of the document irradiate light to the front surface and the rear surface of the document, the light irradiated toward the front surface of the document interferes with the light irradiated toward the rear surface of the document. Thus, the information about the image recorded on the document is distorted, and a scan quality may be deteriorated.